Liners provide a soft, flexible interface between a residual limb of an amputee and a hard socket to which a prosthetic device is secured. Such liners are typically made of an elastomer material such as silicone. Such liners may also be used in connection with orthotic devices. Suspension sleeves are a flexible tube used to secure the prosthetic device to the patients limb. The sleeve may be a sealing sleeve, or a suspension sleeve. Both types start on the prosthetic device and finish on the patients limb. Supportive sleeves can be used in an orthotic device to support a joint or limb of a patient.
Prosthetic suspension liners are described in prior patents, and may be fabricated of elastomer or rubber materials, and are used to cushion a post-operative stump or residual limb with respect to a prosthesis that is installed over the residual limb and coupled to the liner, e.g. by a conventional locking device.
Such liners should conform closely with the residual limb, accommodate all surface contours and sub-surface bone elements of the residual limb, and provide a comfortable cushion between the residual limb and the hard socket of the prosthesis that is to be fitted over the residual limb. Various silicone rubber or elastomer materials are used for suspension liners. Such elastomer materials having an appropriate hardness/softness, elongation, tensile, and other properties, such as bio-inertness (resulting in no skin reaction), have been successfully used for suspension liners.
The elastomer forming the liner or sleeve frictionally engages and remains attached to the skin of a residual limb so that the limb is retained within the prosthetic socket in a comfortable, non-irritating manner. For example, liners may be used for any level of amputation both upper and lower limb.
When an amputee walks air inside the socket allows the socket to fall away from the amputee during swing phase (the time the prosthesis is in the air between steps) causing an accelerated impact of the residual limb and the bottom of the socket when the heel hits the floor. By removing the air in the socket the prosthesis is held closer to the residual limb during swing phase reducing the accelerated impact at heel strike. There are various ways to seal the proximal portion of the socket and the liner that covers the amputee's residual limb. The most common is the use of a sealing sleeve. The sealing sleeve is attached to the outside of the socket and extends up onto the amputee's limb usually sealing on the liner.
Problems with sealing sleeves include, but are not limited to, punctures, bunching behind the knee, restricted knee flexion, and tearing along the brim of the socket.
U.S. Pat. No. 7,025,793 to Egilsson is directed to a seal but it is attached directly to the liner, which does not allow for optimal placement of the seal. The design configuration may not allow for higher vacuum sockets. Another existing seal is disclosed in U.S. Pat. No. 7,144,429 to Carstens. The seal arrangement includes a cuff-like base with a sealing lip on an outside thereof. The lip has two flaps to seal on both the liner and inner socket wall but nothing to hold the base in place, which may allow for the possibility of migration of the seal proximally during donning of the liner, compromising the seal.